1. Field of the Invention
This invention relates to an improvement in a slurry type of hydrogen treatment of a heavy hydrocarbonaceous oil. It particularly relates to the hydrorefining or hydroconversion of a heavy hydrocarbonaceous oil comprising a catalyst dispersed in the oil.
2. Description of the Prior Art
Hydrorefining processes utilizing dispersed catalysts in admixture with the hydrocarbonaceous oil are well known.
U.S. Pat. No. 3,161,585 discloses a hydrorefining process in which a petroleum oil chargestock containing a colloidally dispersed catalyst selected from the group consisting of Groups VB and VIB, an oxide of said metal and a sulfide of said metal is reacted with hydrogen at hydrorefining conditions.
It is also known to use finely divided Group VIII metal components in a catalytic slurry process for the hydrogenative conversion of heavy oils. See, for example, U.S. Pat. Nos. 1,876,270; 2,091,831; 3,617,503; 3,297,563 and 3,622,498.
It is known to separate in the same still a hydrocarbonaceous feed and reaction products of a hydrocarbon conversion process (see, for example, U.S. Pat. No. 2,773,017).
It is also known to recycle a slurry of oil and solids from a fractionator to a reactor (see, for example, U.S. Pat. No. 2,464,810).
U.S. Pat. No. 3,297,563 discloses a slurry hydrotreating process in which a bleed stream of slurry is removed from the hydrotreating reactor.
In the slurry type of hydrorefining or hydroconversion process utilizing heavy oil feeds, the effluent of the reaction zone contains catalytic solids in the liquid product. Regardless of the method of concentrating the solids, the liquid product, for example, of a hydroconversion zone, will generally be separated into normally liquid lighter boiling converted material and higher boiling unconverted material. The conventional practice is to utilize a first pipestill to separate a hydrocarbonaceous oil into fractions, at least one of which will be used as feed for the hydrogen treating zone, and subsequently, passing the liquid product effluent of the hydrogen treating zone with or without solids to a second pipestill to separate the liquid product into fractions.
It has now been found that the second pipestill can be omitted by recycling the liquid product of the hydrogen treating zone to the pipestill used to obtain the oil feed for the hydrogen treating zone. Furthermore, the coarser solids are removed from the reactor to obtain a purge of solids from the system.